The famous Ring Nebula (also catalogued as Messier 57, M57 or NGC 6720) appears in the northern constellation of Lyra. It is a prominent example of a planetary nebula. This is a shell of ionized gas expelled into the surrounding interstellar medium by a red giant star, which was passing through the last stage in its evolution before becoming a white dwarf.
Read more about Ring Nebula: History, Observation, Properties
Famous quotes containing the word ring:
“I was exceedingly interested by this phenomenon, and already felt paid for my journey. It could hardly have thrilled me more if it had taken the form of letters, or of the human face. If I had met with this ring of light while groping in this forest alone, away from any fire, I should have been still more surprised. I little thought that there was such a light shining in the darkness of the wilderness for me.”
—Henry David Thoreau (1817–1862)